Occultation event with (1872) Helenos, event index number 4364
Regions able to see the event: Europe
Geocentric closest approach at 2026/10/09 02:08:02 UTC
J2000 position of star is 05:07:08.3 +08:52:48
Equinox of date position of star is 05:08:36.1 +08:54:48
Star is 99 degrees from the moon. Moon is 3% illuminated.
Stellar brightness G=13.3, apparent brightess of occulting body is G=16.4
Use an exposure time of 0.13 seconds with the standard RECON-QHY system.
SNR of 9.6 per integration for unocculted signal
Expected flux drop is 94% with SNR of 9.1 for the occulted depth (per occulted point)
Apparent velocity is 7.8 km/sec on the sky relative to the star, or, 7.9 arcsec/hr.
Position angle of asteroid motion is 13.7 degrees
The recommended exposure time corresponds to 1.0 km per image.
The 1-sigma error in the time of the event is 4.4 seconds.
The 1-sigma cross-track error in the shadow position is 8.5 km.
The sky-plane scale is 3561.8 km/arcsec.
Diameter estimates:
42.1 km assuming a 5% albedo, maximum of 5.4 sec for a central chord
17.2 km assuming a 30% albedo, maximum of 2.2 sec for a central chord
Cross-track diameter of 34.0 km used for deployment plan.
Star training set for 1872_Helenos, (2026/10/09 02:08UT) Object RA Dec mag sep mel Aldebaran 04:37:27.6 +16:33:39 0.8 10.77 107 Bellatrix 05:26:34.1 +06:22:18 1.6 5.13 95 14 Ori 05:09:20.5 +08:31:53 5.7 0.42 99 PPM 148418 05:06:40.8 +08:58:38 7.2 0.48 100 PPM 148502 05:09:45.7 +08:50:01 8.9 0.30 99 PPM 148481 05:09:14.6 +08:45:55 10.9 0.22 99 1872_Helenos 05:08:36.1 +08:54:48 16.4 99 Positions are for equinox of date
Star training set for 1872_Helenos, (2026/10/09 02:08UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 10.77 107 Bellatrix 05:25:07.8 +06:20:58 1.6 5.13 95 14 Ori 05:07:52.9 +08:29:53 5.7 0.42 99 PPM 148418 05:05:13.0 +08:56:32 7.2 0.48 100 PPM 148502 05:08:18.0 +08:48:03 8.9 0.30 99 PPM 148481 05:07:46.9 +08:43:56 10.9 0.22 99 1872_Helenos 05:07:08.3 +08:52:48 16.4 99 Positions are for J2000